On Tue, Feb 09, 2021 at 11:24:03AM +0800, Jason Wang wrote:
On 2021/2/9 上午2:38, Michael S. Tsirkin wrote:
On Mon, Feb 08, 2021 at 05:17:41PM +0100, Stefano Garzarella wrote:
It's legal to have 'offset + len' equal to
sizeof(struct virtio_net_config), since 'ndev->config' is a
'struct virtio_net_config', so we can safely copy its content under
this condition.
Fixes: 1a86b377aa21 ("vdpa/mlx5: Add VDPA driver for supported mlx5 devices")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Stefano Garzarella <sgarzare@xxxxxxxxxx>
---
drivers/vdpa/mlx5/net/mlx5_vnet.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
index dc88559a8d49..10e9b09932eb 100644
--- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
+++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
@@ -1820,7 +1820,7 @@ static void mlx5_vdpa_get_config(struct vdpa_device *vdev, unsigned int offset,
struct mlx5_vdpa_dev *mvdev = to_mvdev(vdev);
struct mlx5_vdpa_net *ndev = to_mlx5_vdpa_ndev(mvdev);
- if (offset + len < sizeof(struct virtio_net_config))
+ if (offset + len <= sizeof(struct virtio_net_config))
memcpy(buf, (u8 *)&ndev->config + offset, len);
}
Actually first I am not sure we need these checks at all.
vhost_vdpa_config_validate already validates the values, right?
I think they're working at different levels. There's no guarantee that
vhost-vdpa is the driver for this vdpa device.
Maybe we can do these checks in the vdpa_get_config() helper and we can
also add a vdpa_set_config() to do the same.
Thanks,
Stefano
Second, what will happen when we extend the struct and then
run new userspace on an old kernel? Looks like it will just
fail right? So what is the plan?
In this case, get_config() should match the spec behaviour. That is to
say the size of config space depends on the feature negotiated.
Thanks
I think we should
allow a bigger size, and return the copied config size to userspace.
--
2.29.2
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